// #define DEBUGGING #include using namespace std; #define endl '\n' #define ALL(V) (V).begin(), (V).end() #define ALLR(V) (V).rbegin(), (V).rend() template using V = vector; template using VV = V>; template using P = pair; using ll = int64_t; using ull = uint64_t; using PLL = P; template const T& var_min(const T &t) { return t; } template const T& var_max(const T &t) { return t; } template const T& var_min(const T &t, const Tail&... tail) { return min(t, var_min(tail...)); } template const T& var_max(const T &t, const Tail&... tail) { return max(t, var_max(tail...)); } template void chmin(T &t, const Tail&... tail) { t = var_min(t, tail...); } template void chmax(T &t, const Tail&... tail) { t = var_max(t, tail...); } template const T& clamp(const T &t, const T &low, const T &high) { return max(low, min(high, t)); } template void chclamp(T &t, const T &low, const T &high) { t = clamp(t, low, high); } namespace init__ { struct InitIO { InitIO() { cin.tie(nullptr); ios_base::sync_with_stdio(false); cout << fixed << setprecision(30); } } init_io; } #ifdef DEBUGGING #include "../debug.cpp" #else #define DEBUG(...) 0 #define DEBUG_SEPARATOR_LINE 0 #endif template T make_v(T init) { return init; } template auto make_v(T init, size_t s, Tail... tail) { #define rec make_v(init, tail...) return V(s, rec); #undef rec } using History = map>; ll rev(ll x, ll y, ll res) { return x == res ? y : x; } ll query(ll x, ll y, History &his) { cout << "? " << x << ' ' << y << endl << flush; ll res; cin >> res; his[res].push_back(rev(x, y, res)); return res; } pair>> calc(V people) { map> history; if(people.size() == 1) return make_pair(people[0], history); while(true) { if(people.size() == 2) { ll res = query(people[0], people[1], history); return make_pair(res, history); } else if(people.size() == 3) { map cnt; for(ll i = 0; i < 3; i++) for(ll j = i + 1; j < 3; j++) cnt[query(people[i], people[j], history)]++; for(auto ele : cnt) if(ele.second == 2) return make_pair(ele.first, history); } V tmp; for(ll i = 0; i + 1 < people.size(); i += 2) tmp.push_back(query(people[i], people[i + 1], history)); if(people.size() & 1) tmp.push_back(people.back()); people = move(tmp); } } int main() { ll N; cin >> N; V people(N); iota(ALL(people), 1); for(ll loops = 0; loops <= 1; loops++) { ll win; History his; tie(win, his) = calc(people); people.clear(); if(loops == 0) people = his[win]; else cout << "! " << win << endl; } return 0; }